1. Field of Invention
The present invention relates to accessories of laser printers, copiers, and fax machines, and more particularly to an aluminum sleeve for magnetic development rollers and its method.
2. Description of Related Arts
The magnetic roller inside the drum is considered as one of the important accessories for a laser printer, copier, and/or a fax machine. The magnetic roller generally comprises an aluminum sleeve having an adsorption layer, a magnetic core received in the aluminum sleeve, a conductive terminal coupled at the end of the aluminum sleeve, and two plastic made insulation covers mounted at two ends of the aluminum sleeve respectively. When the magnetic core generates a magnetic field, the toner (carbon powder) is attached to the absorption layer of the aluminum sleeve. Once the magnetic roller is electrified, the aluminum sleeve transforms the array of the toner to the photoreceptor surface of the imaging drum. Therefore, the printing performance of the machine is directly affected by the quality of the absorption layer of the aluminum sleeve. Accordingly, the magnetic roller is generally constructed by the aluminum sleeve having the absorption layer at its outer surface, and a shaft extended at one end of the aluminum sleeve for gear engagement. However, the two methods have the drawbacks that the absorption layer may attach coarse particles and the particles are unevenly attached on the absorption layer. In addition, the manufacturing process is relatively complicated and the manufacturing cost is relatively expensive. The China patent, from our company 200420051571.X entitled “advance aluminum sleeve for magnetic rollers”, teaches the aluminum sleeve has an absorption layer for overcoming the drawbacks of coarse and uneven particles by the conductive coating or sandblasting methods. However, in actual use, the absorption layer of the aluminum sleeve is more easily oxidized and its wearing resistance is poor. The oxidation of the absorption layer will affect the performance of the magnetic roller while the poor wearing resistance of the absorption layer will reduce the service life span of the aluminum sleeve.